Forty-one participants were enrolled into this multi-site, outpatient, open-label, ten-week trial. Participants were scheduled to attend three visits per week to allow safety and efficacy measures to be taken. In addition, participants were given two hours of individual substance abuse therapy during the first four weeks, and one hour per week during the last six weeks, of the trial. All participants were started on a total daily dose of 20 mg MPD. The total daily dose was then increased to a maximum daily dose of 60 mg (20 mg TID) or to the maximum dose tolerated by the participant.